The Flow Cytometry Shared Resource provides cell analysis and cell sorting services for cancer research in the Stanford community. The mission of the Flow Cytometry Shared Resource is to (1) promote cancer research and training for cell-based assays at the highest level of quality and rigor, (2) bring new developments in instrumentation, technique and analysis for preclinical use in the Stanford research community, and (3) support early clinical trial analysis in patient management. The Flow Cytometry Shared Resource enhances the productivity and effectiveness of research by promoting high-content data acquisition, assuring the highest data quality and consistency, carrying out efficient cell sorting, providing reliable data management, educating and training researchers and consulting in experiment design and evaluation. A large majority (88%) of current use in this Shared Resource is by Cancer Center members. In fiscal year 2005, the Flow Cytometry Shared Resource provided approximately 12,500 hours of cell analysis and cell sorting service to 490 individual researchers in the laboratories of 97 Stanford investigators. An oversight committee provides recommendations on Shared Resource policies and activities, ensuring that this Shared Resource is aligned with the Cancer Center's strategic goals. This Shared Resource has been at the cutting edge in the development of stem cell analysis and intracellular signaling analysis in leukemia and other cancers. It will greatly facilitate new understanding of stem cells in cancer, development of bioinformatics tools for analysis of complex flow cytometric datasets, patient cell analysis, and early development of biomarkers for patient stratification.